update on hiv testing - nastad.org · ortho vitros eci/eciq ... received results 250 100.0% 430...
TRANSCRIPT
Update on HIV Testing
Bernard M. Branson, M.D.
Associate Director for Laboratory Diagnostics
Division of HIV/AIDS Prevention
Centers for Disease Control & Prevention
The views expressed in this presentation are those of the author and do not
necessarily represent those of the Centers for Disease Control and Prevention
Outline
Changes in HIV testing technology
Detecting Acute HIV Infection
HIV-2
New HIV diagnostic testing algorithm: emphasis
on sensitivity
Follow-up testing
Evolution of HIV Tests
1st generation: whole viral lysate, detects IgG antibody
2nd
generation: synthetic peptides, detects IgG antibody
3rd
generation: detect IgM and IgG antibody
4th
generation: detects IgM, IgG antibodies, p24 antigen
“Combi” tests: detect both HIV-1 and HIV-2 antibodies
Nucleic acid tests: detect HIV RNA
HIV Infection and Laboratory Markers
HIV RNA (plasma)
HIV Antibody
0 10 20 30 40 50 60 70 80 90 100
HIV p24 Ag
22
1st
gen
2nd
gen
3rd
gen
Days
Modified after Busch et al. Am J Med. 1997
Infection 4th
gen
IgM
IgG
Uni-Gold Recombigen
OraQuick
Advance Clearview Complete
Clearview Stat Pak INSTI
CLIA-Waived
Point-of-Care
Rapid HIV Tests
DPP HIV-1/2 Assay
CLIA moderate complexity
for serum, plasma, oral fluid
“SampleTainer” = residual
specimen after testing
FDA-approved Dec 21, 2012
Determine Combo Rapid HIV 1/2 Ag/Ab Test
CLIA moderate complexity
Distinguishes Ag from Ab
Whole blood, serum plasma
FDA-approved August 2013
On-board Refrigeration of Multiple Different Assays
Random Access Multiplatform
analyzers for HIV testing
STAT sample requests without pausing
Results in <60 minutes
Random Access Multiplatform
analyzers for HIV testing
ADVIA® Centaur™ HIV 1/O/2 Enhanced (EHIV)
Chemiluminescent
immunoassay
3rd
generation format
- HIV-1: gp41, p24
- HIV-2: gp36
- group O
Time to result <1 hour
FDA-approved July 2006
Ortho VITROS ECi/ECiQ
Chemiluminescent
immunoassay
3rd
generation format
- HIV-1: gp41, gp120, p24
- HIV-2: gp36
- group O
Time to result <1 hour
Repeat only borderline results
FDA-approved March 2008
Chemiluminescent
immunoassay
Detects p24
antigen and HIV
antibody
Time to result: 29
minutes
FDA-approved
June 22, 2010
Abbott Architect 4th
Generation Ag/Ab
Combo Assay
Bio-Rad GS HIV Combo Ag/Ab EIA
Microwell plate EIA
4th generation:
- HIV-1: gp160
- HIV-2: gp36
- Group O
p24 antigen
FDA-approved July 25, 2011
Relative Seroconversion Sensitivity
0.00
0.10
0.20
0.30
0.40
0.50
0.60
0.70
0.80
0.90
1.00
-50 -40 -30 -20 -10 0 10 20 30
Genprobe
Architect 4th
BioRad 4th
Advia 3rd
Vitros 3rd
Abbott 3rd
BioRad 3rd
Insti
Multispot
Reveal
Statpak
Complete
Unigold
Oraq Adv
Cu
mu
lative
fre
qu
en
cy o
f p
ositiv
e t
ests
days to WB positive
26 seroconverters were analyzed with 14 tests 17 seroconverters with WB positive used for cumulative frequency analysis
Sequence of Test Positivity Relative to WB (plasma)
166 specimens, 17 Seroconverters - 50 % Positive Cumulative Frequency
Modified from Masciotra et al, J Clin Virol 2011, 2013
Days before WB positive
WB
po
sitive
AP
TIM
A (-
26
)
GS 1
/2
+O
(-
12
)
Mu
lti-Sp
ot (-
7)
Reveal G
3,
(-6
)
Viro
no
stka (+
2)
OraQ
uick (-1
)
Un
igo
ld
(-2
)
25
20
10
5
0
15
Arch
itect A
g/A
b C
om
bo
(-
20
)
CO
MP
LET
E H
IV
-1
/2
(-5
)
HIV
-1
/2
STA
T-PA
K (-5
)
Ad
via (-
14
)
Vitro
s (-
13
)
IN
ST
I (-
9)
Bio
-R
ad
A
g/A
b C
om
bo
(-1
9)
and Owen et al, J Clin Micro 2008
DPP
Determ
in
e A
g/A
b C
om
bo
(-
15
)
+40
Oral Flu
id
Luo et al,
J Clin Virol
2013
Avioq
,
(A
vioq
)
HIV RNA (plasma)
HIV Antibody
0 10 20 30 40 50 60 70 80 90 100
HIV p24 Ag
22
1st
gen
2nd
gen
3rd
gen
Days
Modified after Busch et al. Am J Med. 1997
Infection 4th
gen
Acute HIV Infection
HIV Infection and Laboratory Markers
Why Does It Matter?
Sensitivity among frequently-tested MSM in Seattle
192 infected with HIV
23 (12%) detected only by RNA
(15/16 tested detected by Ag/Ab immunoassay)
169 (88%) detected by serum Ab immunoassay
153 (80%) detected by oral fluid rapid test
- Stekler et al, Clin Inf Dis 2009
Performance of 4 antibody tests –
Clinical Testing, San Francisco
Test Acute HIV Established HIV All HIV Sensitivity
Oraquick Oral 0/11 110/116 (94.8%) 110/127 86.6%
OraQuick fingerstick 0/18 226/228 (99.1%) 226/246 91.9%
Vironostika EIA 0/22 262/262 (100%) 262/284 92.3%
GS EIA 3/7 (27.3) 97/97 (100%) 100/104 96.2%
Pilcher et al, PLoS One 2013
Houston, Texas Hospitals, 2011-2013
3rd
generation laboratory testing, 2 hospitals
238 repeatedly reactive EIA, Western blot
negative or indeterminate
Sent for NAT testing
26 (10.9%) positive = acute HIV infection
Policy Implications
Texas Department of State Health Services
HIV testing must use blood-based specimens (finger stick
or venipuncture).
Confirmatory testing must be collected by venipuncture
on-site immediately after a point-of-care (e.g., rapid)
preliminary positive test result.
After a reactive immunoassay, all indeterminate and
non-reactive confirmatory tests must be automatically
referred for a NAAT to determine if a client has an acute
HIV Infection.
- Effective June 1, 2014
4th Generation Ag/Ab Assay vs. RNA
RNA+/ 3rd
gen-negative specimens detected by
4th
generation EIA:
38 of 46 (83%) – Australia*
10 of 14 (71%) – CDC AHI study**
51 of 61 (84%) – CDC panel***
4 days after RNA – 9 seroconversion panels***
* Cunningham P, HIV Diagnostics Conf 2007
** Patel P, CROI 2009 *** Owen M, CROI 2009
Phoenix ED Screening July 2011 through
February 2013
4th
gen screening of patients who had blood drawn
15% of patients declined testing
13,014 patients tested
37 (0.3%) new HIV infections
12 (32.4%) had Acute HIV Infection (antibody negative)
Median viral load:
Acute infection: 3.6 million copies/ml
Established infection: 27,125 copies/ml
Limitations of Antibody Testing
Antibody tests do not detect infection in ~ 10% of
infected persons at highest risk of transmission
Western blot confirmation is less sensitive during
early infection than many widely used screening
tests
Antigen/antibody combo tests now FDA-approved
that can detect most antibody-negative persons
during highly infections acute infection stage
HIV-2 Infection
Remains uncommon in U.S., but
Does not respond to NNRTIs, some PIs (first line therapy)
Undetectable by HIV-1 viral load tests
Misclassification by HIV-1 Western blot:
54/58 (93%) HIV-2 patients tested had positive HIV-1 WB (NYC)*
97/163 (60%) HIV-2 cases reported had positive HIV -1 WB (CDC)**
HIV-2 often diagnosed after immunologic deterioration
in patient with negative viral load
*Torian et al, Clinical Infectious Disease 2010
**MMWR July 2011
4th generation HIV-1/2 immunoassay
HIV-1/HIV-2 antibody differentiation immunoassay
(-) (+)
HIV-1 (+)
HIV-2 (-)
HIV-1 antibodies
detected
HIV-1 (-)
HIV-2 (+)
HIV-2 antibodies
detected
HIV-1 (-) or indeterminate
HIV-2 (-)
NAT
NAT (+) Acute HIV-1 infection
NAT (-) Negative for HIV-1
Negative for HIV-1 and HIV-2
antibodies and p24 Ag
HIV-1 (+)
HIV-2 (+)
HIV antibodies
detected
NAT: nucleic acid test (e.g., RNA)
FDA-approved HIV-1/HIV-2
Antibody Differentiation Assay
34
Peptide HIV-2
Recombinant HIV-1
Peptide HIV-1
Reactive
Control
Nucleic Acid Test (NAT) for Diagnosis
APTIMA HIV-1 qualitative RNA assay is only NAT
FDA-approved for diagnosis
Clinicians can order HIV-1 viral load tests, but labs
cannot use them as a reflex part of the algorithm
APHL and CDC contracted 2 referral laboratories
(NY State and FL) as reference laboratories for
APTIMA from other public health labs
Implementation: Massachusetts
First 12 months
7,984 specimens tested
258 (3.2%) positive for HIV-1
1 (0.01%) positive for HIV-2
8 (0.10%) acute HIV infections
6 = EIA negative, WB negative
2 = EIA reactive, WB indeterminate
http://www.aphl.org/AboutAPHL/publications/
Documents/ID_2013Nov_HIV-Reporting-
Language.pdf
(Search: APHL HIV Reporting Language)
Using Rapid HIV Testing
Algorithms to Improve the
Accuracy of HIV Testing, Receipt
of Test Results, and Linkage to
Care
- Delaney et al, CROI 2011
Intervention
Rapid test algorithm
Clients with a preliminary-positive test have blood
drawn for standard (offsite) confirmatory testing
Up to 2 additional rapid blood tests
2 positive rapid tests = same day referral for
HIV care
Los Angeles: 4 sites San Francisco: 5 sites
Comparison
Rapid test with laboratory confirmation
Clients with a preliminary-positive test had blood
drawn for standard offsite confirmatory testing
Appointment scheduled (usually for 7 days later)
to receive confirmatory test results
Referral if confirmatory test positive
Los Angeles: 12 sites San Francisco: 11 sites
Intervention Sites
Comparison Sites
N % N %
False-positive rapid test 37 14.8% 124 13.6%
Confirmed positive 213 85.2% 791 86.4%
Positive on multiple
rapid tests 213* 100.0%
Received results 250 100.0% 430 47.0%
*Includes one client who tested (false) negative on the 2nd
test before testing positive on a third rapid test
Results
1004 HIV-
infected persons
eligible for
linkage
181 Tested
anonymously
48 Reside out of
surveillance
jurisdiction 775 HIV-
infected
individuals for
engagement in
care analysis
Only 179 from
intervention sites
In Care (CD4/VL) within 3 Months
Days since HIV-positive test result
Estimates of Time from Diagnosis to First Reported CD4 or Viral Load
P
rop
ort
ion
wit
h e
vid
ence
of
care
en
gage
men
t
Intervention
Comparison, received referral
Comparison, no referral
Conclusions
PPV: rapid test algorithm 100%; single rapid test 85%
Engaged in care <90 days:
67% of clients who received referral
50% of clients who did not return for confirmatory
results or receive referral
Referral to care after reactive rapid test is essential
There is no legislative requirement for a “confirmed” HIV
diagnosis prior to linkage to RWHAP-funded medical care,
nor is there any specific statutory or program requirement
related to the use of Western blot.
Having positive results from only one HIV antibody test
should not be a barrier to linkage to care to a RWHAP-
funded clinic or other HIV care providers.
Three Options for Referral
Refer only after positive supplemental test
Some patients will seek care without 2nd
test result
Refer to care after 2 reactive rapid tests
Positive/negative rapid test results still require follow-up
testing because small percentage are HIV-positive
Refer to care after one reactive rapid test
Small percentage patients will be HIV-negative
Arrange specific intake for additional testing
Additional Information
2011 Journal of Clinical Virology Supplement
Open access:
www.journalofclinicalvirology.com
2013 Journal of Clinical Virology Supplement
Open access:
www.journalofclinicalvirology.com